Portion of a keyboard



FIG. 1 is a top view of a portion of a keyboard showing our new design;

FIG. 2 is a perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a right side view thereof; and,

FIG. 6 is a left side view thereof.

The broken line showing of the keys is for illustrative purposes only and forms no part of the claimed design. The unshown bottom of the keyboard forms no party of the claimed design. 

The ornamental design for a portion of a keyboard, as shown and described. 